Why? I say keep them on, because the more you take CNC backings on and off the harder they are to get back on I find. Maybe it's just me. Lol But yeah, definatelly worth the extra money man. Better lever feel, better brake performance, Cheaper in the long run, less play, and they won't snap on you like plastic backings sometimes do. ONLY disadvantage is that after a long time they sometimes snap your piston. I've seen it happen to two of my mates.